Honing tool

ABSTRACT

The present invention relates to a honing tool and a method for honing the inner surface of an opening in a workpiece with a honing tool according to the invention.

BACKGROUND

The present invention relates to a honing tool for honing the innersurface of an opening in a workpiece according to the preamble of claim1, as well as a method for honing the inner surface of an opening in aworkpiece with such a honing tool.

During honing, the respective honing tool is inserted into the openingto be machined. To this purpose, the honing tool can be moved into thestationary opening, or the workpiece with the opening can be movedrelative to the stationary honing tool such that the honing tool isinserted. Subsequently, the movement of a rotation with superimposed upand down movement of the honing tool in the opening is carried out,which is typical for honing. Also in this case, the workpiece or thehoning tool or both can be moved so that the corresponding relativemovement between workpiece and honing tool is present.

When honing the openings, in particular bores, these openings haveusually been machined in preceding steps, wherein a nominal dimension ofthe openings is often not achieved with sufficient certainty andaccuracy by the preceding steps. In order to ensure that the opening tobe honed has a nominal dimension, a check measurement is usually carriedout prior to honing. Two honing operations are often required duringhoning. For example, the first honing operation may aim at a correctionof diameter and shape accuracy, and the second honing operation can beused to smooth the surface. Honing machines usually have a separatehoning station with a respective separate honing tool for each of thesehoning steps. It is often desired or necessary to check the result ofthe respective honing process at an additional re-measuring station. Theexecution of these possibly quite numerous working steps requirescomplex honing machines and an extensive workpiece transport within thehoning machine.

It is an object of the present invention to provide a honing tool thatenables an operation of a honing machine which is as efficient aspossible. Furthermore, it is an object of the present invention toprovide a method which enables machining of an opening as efficient aspossible and with a short processing time.

These objects are achieved by the honing tool according to claim 1 or bythe method according to claim 15, respectively.

The honing tool according to the invention is formed with a tool bodyextending in an axial direction and having a honing section whichcomprises a group of hone strips, wherein the honing tool comprises aworkpiece checking element for checking a size and/or a position of theopening the workpiece checking element being arranged on the tool bodyso as to be movable relative to the tool body preferably in the axialdirection. It is also conceivable that the workpiece checking element isarranged so as to be movable in a radial direction relative to the toolbody, in order to check whether the opening in the workpiece has asufficient opening width and/or to check for a positioning or alignmenterror of the opening of the workpiece when the honing tool moves intothe opening.

The present workpiece checking element is therefore not used to monitorthe honing process, but to check whether the workpiece to be machinedhas been correctly positioned or has been correctly machined in apreceding working step. This checking can be carried out by means of theworkpiece checking element during the insertion operation, so that aseparate pre-checking can be omitted. The workpiece checking element isthus designed and arranged to monitor the insertion operation of thehoning tool. By means of the workpiece checking element it is thereforepossible to check during the insertion operation whether the same can becarried out as intended. In other words, in contrast to measuringstrips, for example, which allow to check the honing process itself, theworkpiece checking element of the honing tool according to the inventionhas nothing to do with the actual machining process of the honing.Rather, the workpiece checking element enables to integrate apre-checking of the alignment or the bore size of the workpiece,respectively, into the insertion operation of the honing tool.Conventionally, such a check of whether the workpiece or its bore has asufficient width and/or is correctly positioned to insert the honingtool was carried out in a separate step using separate measuringdevices.

In particular, the honing tool according to the invention is a honingtool for machining an opening in a gear wheel.

The workpiece checking element can be used in particular to ensure thatthe opening in the workpiece has a sufficient opening width, e.g. that anominal dimension has been achieved in preceding machining steps. Theworkpiece checking element can also or additionally serve to exclude apositioning or alignment error of the opening of the workpiece.

In particular, if the opening in the workpiece does not have asufficient opening width, the honing tool may be damaged whenconventional honing tools are inserted. For this reason, the openingwidth is usually checked for a nominal dimension at a preceding workingstation. The movable support of the workpiece checking element allows toinsert the honing tool into the opening, wherein if the opening width ofthe opening is less than the specified dimension, the workpiece checkingelement contacts the inner surfaces of the opening, whereupon theinsertion operation can be interrupted. The movable arrangement of theworkpiece checking element relative to the tool body ensures thatneither the honing tool nor the workpiece will be damaged. In otherwords, the present honing tool now offers the possibility to check forsufficient width and correct alignment of the opening by means of theworkpiece checking element during insertion, while there is no risk ofdamaging the bore or the hone strips, which could be damaged by“hitting” the bore wall if the opening width is too small or if theopening is inclined.

The term of inserting the honing tool into the opening or respectivemoving or retracting the honing tool must not be understood in arestrictive way within the meaning of the present application. The aboveterms refer to a relative movement between the honing tool and theworkpiece. For example, the workpiece can be held stationary and thehoning tool can be moved, or the honing tool can be held stationary andthe workpiece can be moved. It is also conceivable to move honing tooland workpiece simultaneously.

Within the meaning of the present application, honing also means arelative movement between the honing tool and the workpiece, wherein thehoning tool and/or the workpiece can be moved. The honing processcomprises a superimposition of translational and rotational relativemovements between the workpiece and the honing tool.

Preferably, the workpiece checking element is coupled to a detectingdevice, the detecting device being adapted to detect a movement of theworkpiece checking element relative to the tool body. Preferably, thedetecting device is coupled to a controller such that the controllerinterrupts the insertion of the honing tool into the opening when thedetecting device detects a movement of the workpiece checking elementrelative to the tool body.

Optionally, the workpiece checking element is resiliently supported onthe tool body. In this manner, the workpiece checking element is alwaysbiased into a designated position and offers some resistance to anymovement. The resilient support can be realized by mechanical springs,preferably metallic springs. Mechanical springs may be designed as coilsprings or leaf springs. It is also conceivable that the workpiecechecking element is resiliently supported via an elastic polymermaterial. A pneumatic or hydraulic suspension of the workpiece checkingelement is also conceivable. A magnetic or electromagnetic suspension ofthe workpiece checking element is also conceivable.

Optionally, the workpiece checking element is biased into an initialposition and is arranged on the tool body such that the workpiecechecking element is moved out of the initial position when the workpiecechecking element comes into contact with the workpiece, in particularduring insertion of the honing tool into the opening of the workpiece.If the workpiece checking element is moved out of its initial position,this can be detected and the honing tool's insertion operation into theworkpiece can be aborted. This reliably prevents any damage of theworkpiece or the honing tool.

Optionally, the workpiece checking element comprises a contact portionfor contacting the workpiece, which contact portion expands in a radialdirection when viewed from a workpiece-side end of the tool body alongthe axial direction. A corresponding workpiece checking element can beinserted with its “tip” into the workpiece and the contact sectioncontacts the edge of the opening if the opening width is less than anominal dimension.

Optionally, the workpiece checking element is ring-shaped, andpreferably extends around the tool body. This results in the opening ofthe workpiece to be checked around the circumference of the honing tool.Preferably, the contact section described above extends around thehoning tool, wherein the contact section may have discontinuities atsome locations along the circumferential direction. The discontinuitiesmay serve for forming a passage for a cooling lubricant so that the samecannot accumulate above the workpiece checking element during honing.

The workpiece checking element can also be formed conical or like atruncated cone. Forming the workpiece checking element as a sphericalsegment is also possible. Preferably, the workpiece checking element hasa radial cross-section which widens in the axial direction when viewedfrom the workpiece in the axial direction. Preferably, a workpiecechecking element according to the embodiments mentioned in thisparagraph is arranged at the workpiece-side end of the tool body or,respectively, forms the part of the honing tool which is closest to theworkpiece in axial direction.

Optionally, the workpiece checking element is arranged, in an axialdirection, between the workpiece-side end of the tool body and thehoning section, or the workpiece checking element forms a workpiece-sideend of the tool body. In this manner, the workpiece checking element isformed, in the direction of insertion, in front of the honing sectionand any damage to the hone strips, for example due to the opening widthof the opening to be machined being too small, is reliably prevented.

Optionally, the honing tool comprises a second honing section comprisinga second group of hone strips, wherein the first honing section isarranged on the tool body spaced apart from the second honing portion inthe axial direction. In this manner, a further honing operation can becarried out with the same honing tool without requiring retraction ofthe honing tool from the opening or any other intermediate step.

Optionally, the honing tool comprises a third honing section comprisinga third group of hone strips, wherein the first honing section and thesecond honing section are arranged on said tool body spaced apart fromthe third honing section in the axial direction. In this manner, afurther honing operation can be carried out with the same honing toolwithout requiring retraction of the honing tool from the opening or anyother intermediate step. Correspondingly arranged fourth, fifth andfurther honing sections are conceivable, wherein the honing sections canpreferably carry out different honing operations.

Preferably, the first honing section is arranged, in the axialdirection, between the workpiece checking element and the second honingsection. It is advantageous that the first honing section is designed toperform a pre-honing operation and the second honing section is designedto perform a final honing operation.

The hone strips of the two honing sections can be arranged offset toeach other in the circumferential direction or can be equally arrangedin the circumferential direction in both honing sections.

Optionally, the workpiece checking element is coupled to a pneumatic orhydraulic actuator such that the pneumatic or hydraulic actuator changesa flow cross-section of a pneumatic or hydraulic checking medium channelwhen the workpiece checking element is moved out of its initialposition. Preferably, the checking medium channel can be supplied withcompressed air. The actuator is preferably rod-shaped and motion-coupledwith the workpiece checking element. Preferably, the actuator isarranged such that it extends into the region of an intersection of thechecking medium channel when the workpiece checking element or actuatoris moved from its initial position. Preferably, the actuator blocks thecrossing of the checking medium channel when the workpiece checkingelement or the actuator is moved from its initial position.

Optionally, the honing tool comprises at least one air measuring nozzlewhich, when viewed in the axial direction, is arranged offset withrespect to the hone strips, in particular, when viewed from aworkpiece-side end of the tool body, behind the hone strips of one ofthe honing sections, preferably of all of the honing sections, and/orcomprises at least one air measuring nozzle which, when viewed in theaxial direction, is located adjacent to the hone strips of the honingsection or of one of the honing sections, respectively, preferablywherein the honing tool comprises at least one air measuring nozzle perhoning section which is arranged adjacent to the hone strips of therespective honing section when viewed in the axial direction. An airmeasuring nozzle within the meaning of the present application may inthis case relate to at least two nozzles communicating fluidically witheach other, which preferably are located opposite to each other in thecircumferential direction.

The term “behind the hone strips” refers to an arrangement in which thecorresponding air measuring nozzle is located behind the hone stripswhen viewed from the workpiece-side end of the honing tool. Such an airmeasuring nozzle is particularly suitable for the subsequent measurementof the result of a honing operation. Such an air measuring nozzle isalso called an air measuring nozzle for re-measuring.

The term “adjacent to the hone strips when viewed in the axialdirection” refers to an arrangement of the corresponding air measuringnozzle in which the air measuring nozzle is located in the region withinthe axial extension of the hone strips, when viewed in the axialdirection. Such an air measuring nozzle is arranged between the honestrips, when viewed in the circumferential direction. Such an airmeasuring nozzle is particularly suitable for in-process measurement ofthe result of a honing operation. Such an air measuring nozzle is alsoreferred to as an air measuring nozzle for in-process measurement,wherein it can also be used for a follow-up check of the result of ahoning operation.

The air-measuring nozzle for re-measuring preferably extends furtheroutwards in radial direction than an air-measuring nozzle for in-processmeasuring. Preferably, the nozzle cross-sections of the air measuringnozzles for re-measurement are smaller than the nozzle cross-sections ofthe air measuring nozzles for in-process measurement. This allows toachieve a higher accuracy during re-measurement.

Preferably, the actuator is arranged such that when the workpiecechecking element or actuator is moved from its initial position, itdisconnects a connection between an air measuring nozzle and a part of ameasuring air channel. In this case, the air measuring nozzledisconnected from the measuring air channel can be an air measuringnozzle for re-measuring or for in-process measuring with a correspondingarrangement relative to the hone strips.

The rod-shaped actuator should be long enough so that, after theinterruption of the checking medium channel, a sufficient additionaloperating displacement can be covered before the insertion of the honingsection is interrupted. Preferably, the honing section is spaced apartfrom the workpiece checking element at least one sixth, preferably onequarter, of its axial extension, preferably also when the latter isdeflected from its initial position.

Optionally, the actuator coupled to the workpiece checking element is apneumatic actuator, and the checking medium channel, the flowcross-section of which is changed by the actuator, is pneumaticallyconnected to a measuring air channel via which at least one airmeasuring nozzle, preferably a plurality of air measuring nozzles, canbe supplied with measuring air. In this manner, the construction of thehoning tool according to the invention becomes particularly simple, asonly a few compressed air channels must be formed in the honing tool.

Optionally, the honing tool comprises an infeed device, by which therespective hone strips of the two honing sections are feedable in theradial direction independently of each other or always simultaneously.If the hone strips of the individual honing sections can be fedseparately, only the corresponding honing section may be fed asrequired. If the hone strips of the honing sections can be fed in radialdirection always simultaneously by the infeed device, the honing tool,in particular the infeed device, may be made simpler and more robust. Aninfeed device can be, for example, a piezo-based actuator for the honestrips, which is particularly suitable if the hone strips shall befeedable individually.

Optionally, the infeed device has an infeed cone for each honing sectionwhich is designed to interact with wedge surfaces of the hone strips inorder to convert an axial movement of an infeed element into a radialinfeed of the hone strips, preferably wherein the infeed cones of thehoning sections are arranged on a single infeed element such that bothinfeed cones are moved upon movement of the infeed element. In thismanner, the honing tool can be constructed particularly easy and istherefore inexpensive to manufacture.

Optionally, the honing tool comprises a brush section. After honing, theopening can further be smoothed and/or deburred by the brush section.Preferably, the honing section(s) and the air measuring nozzle(s) arelocated between the brush section and the workpiece-side end of the toolbody, when viewed in axial direction.

Optionally, a tool guide is arranged on the honing tool in the region ofthe workpiece-side end of the tool body. Such a tool guide is providedin order to rigidly support the honing tool with respect to a guidebush. Such a design of the honing tool is usually used together with afloating support or cardanic support of the workpiece. Part of theinvention is therefore also a honing machine having a honing tool, whichis formed with the tool guide described above, and a guide bush, whichis designed to accommodate the tool guide. Preferably, such a honingmachine comprises a device for the floating support or cardanic supportof the workpiece.

Part of the invention is also a method for honing the inner surface ofan opening in a workpiece, in particular in a gearwheel, with a honingtool according to one or more of the above-described embodiments, themethod comprising the following steps in succession:

(a) axially inserting the honing tool into the opening and pre-checkingthe width and/or position of the opening in the workpiece by means ofthe workpiece checking element;

b) honing the opening by the hone strips of the honing section,preferably measuring the opening width via an air measuring nozzle;

preferably c) axially moving the honing tool, in particular furtheraxially inserting the honing tool into the opening, and re-measuring theopening width via an air measuring nozzle which is spaced apart from thehoning section of step b) in the axial direction;

preferably d) axially moving the honing tool, in particular furtheraxially inserting the honing tool into the opening, and subsequentlyhoning the opening by the hone strips of the second honing section,preferably measuring the opening width via an air measuring nozzle whichis arranged adjacent to the hone strips of the second honing sectionwhen viewed in the axial direction;

preferably e) re-measuring the opening width via an air-measuring nozzlewhich is arranged adjacent to the hone strips of the second honingsection of step d) when viewed in the axial direction, or axially movingthe honing tool, in particular further axially inserting the honing toolinto the opening, and re-measuring the opening width via anair-measuring nozzle which is spaced apart from the second honingsection of step d) in the axial direction;

preferably f) axially moving the honing tool, in particular furtheraxially inserting the honing tool into the opening, and subsequentbrushing the opening by the brush section of the honing tool;

g) axially retracting the honing tool from the opening.

The term “the following steps in succession” means that the stepsmentioned are carried out temporally one after the other in the ordermentioned, but further steps can be carried out between the stepsmentioned. The method according to the invention allows to carry out apre-checking and a honing operation and, if necessary, one or morein-process measurements or re-measurement(s) and, if necessary, afurther honing operation with a single insertion operation.Conventionally, such a sequence of machining and measuring stepsrequired individual working steps, which were often associated withfurther workpiece transport. The method according to the inventionallows to carry out the complete machining at a single working stationwith a single insertion and retraction operation of the honing tool.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics, application possibilities and advantages of theinvention can be derived from the following description of embodimentsof the invention, which are explained on the basis of the drawings,wherein the characteristics can be essential for the invention, bothsingly and in different combinations, even if this is not explicitlypointed out again.

FIG. 1 is a side view of a honing tool according to the invention;

FIG. 2 is a sectional view of the honing tool of FIG. 1;

FIG. 3 is a sectional view of the honing tool of FIG. 1 in anothersectional plane;

FIG. 4 is a sectional view of the honing tool of FIG. 1 in anothersectional plane;

FIG. 5 is a sectional view of the honing tool of FIG. 1 in anothersectional plane;

FIG. 6 is a sectional view of another honing tool according to theinvention;

FIG. 7 is a sketch of a sequence of the method according to theinvention;

FIG. 8 is a sketch of an alternative sequence of the method according tothe invention; and

FIG. 9 is a sketch of an alternative sequence of the method according tothe invention.

DETAILED DESCRIPTION

In the following Figures, corresponding components and elements have thesame reference signs. For the sake of better clarity, not all referencesigns are shown in all Figures.

FIG. 1 shows a honing tool 10 according to the invention for honing aninner surface 12 of an opening 14 in a workpiece 16, wherein workpiece16 is not shown in FIG. 1. Honing tool 10 comprises a tool body 17 whichextends in an axial direction A from a workpiece-side end 18 to aworkpiece-far-side end 20. At workpiece-far-side end 20, honing tool 10has a coupling section 22, and an infeed pin 24 protrudes from thehoning tool.

Adjacent to coupling section 22, honing tool 10 comprises a connectionsection 25. In the region of connection section 25, honing tool 10comprises a first connection 26 for measuring air and a secondconnection 28 for measuring air. Connections 30 for a cooling lubricantare also located in the region of connection section 25.

Adjacent to connecting portion 25, honing tool 10 comprises a functionalportion 32. In the present embodiment, a workpiece checking element 34,a first honing section 36, a second honing section 38, and a brushsection 40 are arranged in functional section 32. Functional section 32also comprises an in-process measuring arrangement 42 with a first airmeasuring nozzle 44 or a plurality of first air measuring nozzles 44,and a follow-up measuring arrangement 46 with a second air measuringnozzle 48 or a plurality of second air measuring nozzles 48.

A tool guide 50 extends from functional section 32 to workpiece-side end18 of honing tool 10. Tool guide 50 is designed to interact with a guidebushing and to axially align honing tool 10 when tool guide 50 isreceived in a corresponding guide bushing.

First honing section 36 has a group of first hone strips 52. Secondhoning section 38 has a group of second hone strips 54. First honingsection 36 may be equipped with hone strips 52 which are designed tocarry out a pre-honing. Second honing section 38 may be equipped withhone strips 54 which are designed to carry out a finishing honing.

The first honing section 36 is located on tool body 17 spaced apart fromsecond honing section 38 in the axial direction A.

Workpiece checking element 34 is movably arranged opposite to tool body17. Workpiece checking element 34 is arranged on tool body 17 withresilient support. For this purpose, workpiece checking element 34 isconnected to tool body 17 via a plurality of coil springs 56.

Workpiece checking element 34 is preloaded (biased) to an initialposition AS which corresponds to the position shown in FIG. 1. In thisexample, the preload is realized by coil springs 56.

Workpiece checking element 34 is arranged on tool body 17 such thatworkpiece checking element 34 is moved out of the initial position ASwhen workpiece checking element 34 comes into contact with workpiece 16.

Workpiece checking element 34 has a contact section 58 for contactingthe workpiece 16. When viewed from workpiece-side end 18 of tool body 17along the axial direction, contact section 58 expands in a radialdirection R.

Workpiece checking element 34 is ring-shaped and extends around toolbody 17.

Workpiece checking element 34 is located, in the axial direction A,between workpiece-side end 18 of tool body 17 and first honing section36. However, it is also within the meaning of the invention if, forexample, workpiece checking element 34 forms the workpiece-side end 18of tool body 17.

FIG. 2 shows a sectional view along line II-II through honing tool 10.In the section plane of FIG. 2, the course of a first measuring airchannel 60 can be seen. Measuring air channel 60 connects firstconnection 26 for measuring air with second air measuring nozzles 48 ofre-measuring arrangement 46.

FIG. 3 also shows a sectional view along line II-II through honing tool10. However, the sectional plane of FIG. 3 is offset from that of FIG. 2in a circumferential direction U. In the sectional plane of FIG. 3, thecourse of a second measuring air channel 62 can be seen. Measuring airchannel 62 connects second connection 28 for measuring air with firstair measuring nozzles 44 of in-process measuring arrangement 42.

FIG. 3 shows that workpiece checking element 34 is coupled to apneumatic actuator 64 or a plurality of such actuators 64 such thatpneumatic actuator 64 changes a flow cross-section of a pneumaticchecking medium channel 66 when the workpiece checking element is movedfrom the initial position AS. Checking medium channel 66 is formed by apart of measuring air channel 62. Actuator 64 is rod-shaped and projectsinto the region of a T-junction 68 of measuring air channel 62. Ifworkpiece checking element 34 is moved in the direction ofworkpiece-far-end 20 of tool body 17, actuator element 64 moves into theregion of T-crossing 68 such that T-crossing 68 is blocked. Thisblocking of T-junction 68 can be detected by a pressure sensor (notshown). The furcation of T-crossing 68, which can be blocked by theactuator 64, forms checking medium channel 66, the flow cross-section ofwhich can be changed by actuator 64.

FIG. 4 also shows a sectional view along line II-II through honing tool10. The sectional plane of FIG. 4 is, however, offset from those ofFIGS. 2 and 3 in the circumferential direction U. The sectional plane ofFIG. 4 shows the course of a cooling lubricant channel 70. Coolinglubricant channel 70 connects connections 30 for the cooling lubricantwith outlets 72 for the cooling lubricant, wherein outlets 72 arearranged in the region of honing sections 36 and 38.

FIG. 5 also shows a sectional view along line II-II through honing tool10. However, the sectional plane of FIG. 5 is offset from those of FIGS.2, 3 and 4 in the circumferential direction U.

In FIG. 5 it can be seen that honing tool 10 comprises an infeed device74 by which the respective hone strips 52, 54 of the two honing sections36 and 38 can always be fed simultaneously in the radial direction R.Infeed device 74 is used to feed the respective hone strips 52, 54 ofthe two honing sections 36 and 38 at the same time.

Infeed device 74 has an infeed element 75 which has a first infeed cone76 and a second infeed cone 78, wherein first infeed cone 76 is assignedto hone strips 52 of first honing section 36 and second infeed cone 78is assigned to hone strips 54 of second honing section 38.

The respective infeed cones 76 and 78 are designed to interact withwedge surfaces 80 and 82 of hone strips 52 and 54, respectively, inorder to convert an axial movement of infeed element 75 into a radialinfeed of hone strips 52 and 54, respectively. Infeed cones 76 and 78 ofboth honing sections 36 and 38 are arranged on the single infeed element75 such that both infeed cones 76 and 78 are moved when infeed element75 moves. The movement of infeed element 75 can be controlled byactuating infeed pin 24. There is a guide pin at the lower end of theinfeed element which guides the infeed element into a stable coaxialposition inside the tool body.

FIG. 6 shows a sectional view along the line II-II through analternative embodiment of a honing tool 10 according to the invention.The sectional plane of FIG. 6 corresponds to that of FIG. 2.

The embodiment shown in FIG. 6 differs from the embodiment of FIGS. 1-5in that a further in-process measuring arrangement 84 with acorresponding air measuring nozzle 86 is arranged in second honingsection 38. With the embodiment of FIG. 6, no re-measuring arrangement46 is provided. However, a re-measuring arrangement 46 can also beprovided in addition to the further in-process measuring arrangement 84.

FIGS. 7, 8 and 9 each illustrate the sequence of a method according tothe invention for honing an inner surface 12 of an opening 14 in aworkpiece 16 using a honing tool 10 according to the invention, whichmay be, for example, honing tool 10 of FIG. 1 (used in the methodsaccording to FIGS. 7 and 8) or FIG. 6 (used in the methods according toFIG. 9). Workpiece 16 is a gear wheel. The method comprises thefollowing steps in sequence:

Step a): axially inserting (illustrated by a corresponding arrow) honingtool 10 into opening 14 and pre-checking, in particular an openingwidth, of opening 14 in workpiece 16 by means of workpiece checkingelement 34.

During the pre-checking, workpiece checking element 34 moves intoopening 14 if opening 14 has a sufficient width (i.e. if opening 14 hasa nominal dimension) and correct axial alignment.

If the width of opening 14 is too small or workpiece 16 is not correctlyaligned, workpiece checking element 34 contacts workpiece 16 withcontact section 58 and workpiece checking element 34 is moved out of theinitial position AS. Since workpiece checking element 34 is coupled toactuators 64 such that actuators 64 change the flow cross-section ofpneumatic checking medium channel 66 formed by the bifurcation ofT-crossing 68 (see FIG. 3) when workpiece checking element 34 is movedfrom the initial position AS, actuators 64 block T-crossings 68 and thuschange the flow cross-section of checking medium channel 66. By changingthe flow cross-section, an increase in pressure can be detected duringthe flow through checking medium channel 66, and the insertion operationof honing tool 10 can be interrupted.

Step b): honing the opening 14 by hone strips 52 of honing section 36(symbolically represented by a double arrow and a curved arrow). Duringstep b) (during or after honing) it is optionally possible to carry outa measurement of the opening width of opening 14 via an air measuringnozzle 44 of the in-process measuring arrangement 42 which is arrangedadjacent to hone strips 52 of first honing section 36 when viewed in theaxial direction A.

The method preferably comprises a step c): axially moving honing tool10, in particular further axially inserting honing tool 10 into opening14, and re-measuring the opening width via an air measuring nozzle whichis spaced apart from honing section 36 of step b) in the axial directionA. This step is not shown in FIGS. 7, 8 and 9.

Preferably, the method comprises a step d): axially moving honing tool10, in particular further axially inserting honing tool 10 into opening14, and then honing opening 14 by hone strips 54 of second honingsection 38. During step b) it is optionally possible to carry out ameasurement of the opening width of opening 14 via an air measuringnozzle 86 of the in-process measuring arrangement 84 which is arrangedadjacent to hone strips 54 of second honing section 38 when viewed inthe axial direction A.

Preferably, the method comprises a step (e): re-measuring the openingwidth via an air measuring nozzle 86 which is arranged adjacent to thehone strips 54 of the second honing section 38 of step d) when viewed inthe axial direction A (this alternative of the method is shown in FIGS.7 and 8); or axially moving honing tool 10, in particular furtheraxially inserting honing tool 10 into the opening 14, and re-measuringthe opening width via an air measuring nozzle 48 which is spaced apartfrom second honing section 38 of step d) in the axial direction A (thisalternative is shown in FIG. 9).

Preferably, the method comprises a step f): axially moving honing tool10, in particular further axially inserting honing tool 10 into opening14, and subsequently brushing the opening 14 by brush section 40 ofhoning tool 10;

g) axially retracting honing tool 10 from opening 14 (not shown).

With the method variant of FIG. 7, workpiece 16 is stationary and honingtool 10 is moved relative to workpiece 16. With the method variantsshown in FIGS. 8 and 9, honing tool 10 is stationary and workpiece 16 ismoved relative to honing tool 10. Both ways of generating a relativemovement between honing tool 10 and workpiece 16 are in the sense ofthis invention.

1. A honing tool for honing an inner surface of an opening in aworkpiece, comprising a tool body extending in an axial direction (A)and having a honing section which comprises a group of hone strips,characterised in that the honing tool comprises a workpiece checkingelement for checking a size and/or a position of the opening, theworkpiece checking element being arranged on the tool body so as to bemovable relative to the tool body, preferably in the axial direction(A), in order to check during the insertion of the honing tool into theopening whether the opening in the workpiece has a sufficient openingwidth and/or to check for a positioning or alignment error of theopening of the workpiece, wherein the workpiece checking element isbiased into an initial position (AS) and is arranged on the tool bodysuch that the workpiece checking element is moved out of the initialposition (AS) when the workpiece checking element comes into contactwith the workpiece, wherein the workpiece checking element is coupled toa detection device which is adapted to detect a movement of theworkpiece checking element relative to the tool body, wherein thedetecting device is coupled to a controller such that the controllerinterrupts the insertion of the honing tool into the opening if thedetecting device detects a movement of the workpiece checking elementrelative to the tool body.
 2. The honing tool according to claim 1,characterized in that the workpiece checking element is arrangedresiliently supported on the tool body.
 3. (canceled)
 4. The honing toolaccording to claim 1, characterised in that the workpiece checkingelement comprises a contact portion for contacting the workpiece whichexpands in a radial direction (R) when viewed from a workpiece-side endof the tool body along the axial direction (A).
 5. The honing toolaccording to claim 1, characterized in that the workpiece checkingelement is ring-shaped, and preferably extends around the tool body. 6.The honing tool according to claim 1, characterized in that theworkpiece checking element is arranged in the axial direction (A)between the workpiece-side end of the tool body and the honing section,or in that the workpiece checking element forms a workpiece-side end ofthe tool body.
 7. The honing tool according to claim 1, characterized bya second honing section comprising a second group of hone strips,wherein the first honing section is arranged on the tool body spacedapart from the second honing section in the axial direction (A).
 8. Thehoning tool according to claim 1, characterized in that the workpiecechecking element is coupled to a pneumatic or hydraulic actuator suchthat the pneumatic or hydraulic actuator changes a flow cross-section ofa pneumatic or hydraulic checking medium channel when the workpiecechecking element is moved out of the initial position (AS).
 9. Thehoning tool according to claim 1, characterized by at least one airmeasuring nozzle which, when viewed in the axial direction (A), isarranged offset with respect to the hone strips, in particular, whenviewed from a workpiece-side end of the tool body, behind the honestrips of one of the honing sections, preferably of all of the honingsections, and/or by at least one air measuring nozzle which, when viewedin the axial direction (A), is located adjacent to the hone strips ofthe honing section or of one of the honing sections, preferably whereinthe honing tool comprises at least one air measuring nozzle per honingsection which is arranged adjacent to the hone strips of the respectivehoning section when viewed in the axial direction (A).
 10. The honingtool according to claim 8, characterised in that the actuator which iscoupled the workpiece checking element is a pneumatic actuator and thechecking medium channel whose flow cross-section is changed by theactuator, is pneumatically connected to a measuring air channel viawhich at least one air measuring nozzle can be supplied with measuringair.
 11. The honing tool according to claim 1, characterized by aninfeed device by which the respective hone strips of the two honingsections are feedable in the radial direction (R) independently of eachother or always simultaneously.
 12. The honing tool according to claim11, characterized in that the infeed device has one infeed cone perhoning section, which is designed to interact with wedge surfaces of thehone strips, in order to convert an axial movement of an infeed elementinto a radial infeed of the hone strips, preferably wherein the infeedcones of a plurality of honing sections are arranged on a single infeedelement such that both infeed cones are moved upon movement of theinfeed element.
 13. The honing tool according to claim 1, characterizedin that the honing tool comprises a brush section.
 14. The honing toolaccording to claim 1, characterized in that a tool guide is arranged onthe honing tool in the region of the workpiece-side end of the toolbody.
 15. A method of honing an inner surface of an opening in aworkpiece with a honing tool for honing an inner surface of an openingin a workpiece, comprising a tool body extending in an axial direction(A) and having a honing section which comprises a group of hone strips,characterised in that the honing tool comprises a workpiece checkingelement for checking a size and/or a position of the opening, theworkpiece checking element being arranged on the tool body so as to bemovable relative to the tool body, preferably in the axial direction(A), in order to check during the insertion of the honing tool into theopening whether the opening in the workpiece has a sufficient openingwidth and/or to check for a positioning or alignment error of theopening of the workpiece, wherein the workpiece checking element isbiased into an initial position (AS) and is arranged on the tool bodysuch that the workpiece checking element is moved out of the initialposition (AS) when the workpiece checking element comes into contactwith the workpiece, wherein the workpiece checking element is coupled toa detection device which is adapted to detect a movement of theworkpiece checking element relative to the tool body, wherein thedetecting device is coupled to a controller such that the controllerinterrupts the insertion of the honing tool into the opening if thedetecting device detects a movement of the workpiece checking elementrelative to the tool body, wherein the method comprises the followingsteps in succession: a) axially inserting the honing tool into theopening and pre-checking, in particular of an opening width, of theopening in the workpiece by means of the workpiece checking element; b)honing the opening by the hone strips of the honing section, preferablymeasuring the opening width via an air measuring nozzle; preferably c)axially moving the honing tool, in particular further axially insertingthe honing tool into the opening, and re-measuring the opening width viaan air measuring nozzle which is spaced apart from the honing section ofstep b) in the axial direction (A); preferably d) axially moving thehoning tool in particular further axially inserting the honing tool intothe opening, and subsequently honing the opening by the hone strips ofthe second honing section, preferably measuring the opening width via anair measuring nozzle which is arranged adjacent to the hone strips ofthe second honing section when viewed in the axial direction (A);preferably e) re-measuring the opening width via an air-measuring nozzlewhich is arranged adjacent to the hone strips of the second honingsection of step d) when viewed in the axial direction (A), or axiallymoving the honing tool in particular further axially inserting thehoning tool into the opening, and re-measuring the opening width via anair-measuring nozzle which is spaced apart from the second honingsection of step d) in the axial direction (A); preferably f) axiallymoving the honing tool, in particular further axially inserting thehoning tool into the opening, and subsequently brushing of the openingby the brush section of the honing tool; g) axially retracting thehoning tool from the opening.